Filters protect heat exchangers and prevent clogging of nozzles, tubes and other narrow passages by removing dirt particles down to micron size, of any specific gravity, from once-through and recirculating cooling water systems. Filters are line pressure powered, self cleaning and available in sizes from 10-10,000. Orival, Inc. Water Filters 213 S. Van Brunt St. Englewood, NJ, 07631